The present invention relates generally to projection television sets, and more particularly to a projection television set enclosure.
Projection television (PTV) sets are a popular alternative to picture tube television sets, as they provide relatively large viewable screens that cannot be efficiently produced using conventional picture tubes. PTV sets typically include an enclosure housing an optical unit, a mirror, and electronic components for receiving and projecting an image onto a screen assembly mounted on the front of the enclosure. The optical unit typically includes three projection tubes having a cathode ray tube (CRT) optically coupled to a projection lens. The three projection tubes project a red, a green, and a blue image on to a screen of the PTV.
The conventional enclosure is typically divided into two compartments, an upper and a lower compartment. The CRTs and the printed wiring boards (PWB) are typically mounted in the lower compartment, the mirror and screen are mounted in the upper compartment, and the projection lens tends to extend from the lower compartment to the upper compartment. The upper compartment is typically sealed tightly in order to protect the inside of the compartment from dust and other foreign materials. The lower compartment typically includes ventilation holes, positioned adjacent the top and bottom of the compartment, to exhaust heat radiating from the CRTs and the PWBs.
Although durable, conventional enclosures or cabinets, which are formed from wood or molded plastic, are typically big, bulky and, as a result, quite heavy. As the screens of the PTVs increase in size, the cabinets become bigger and heavier. In an effort to reduce the size and weight of the PTVs, manufacturers have begun shrinking the size of the cabinets. However, shrinking a conventional cabinet to reduce the size and weight of a PTV, means shrinking the lower compartment. When the lower compartment is shrunk, much of the peripheral space surrounding the CRTs and PWBs is eliminated and the ventilation holes are drawn closer together. As a result, heat radiation problems tend to arise that can lead to deterioration in component performance and reliability.
Therefore, it would be desirable to provide a durable PTV cabinet that is lighter and smaller, and that includes high heat radiation performance characteristics.
The present invention is directed to an improved enclosure or cabinet for PTVs. The PTV enclosures or cabinets of the present invention tend to reduce the overall weight and size of the PTVs, and improve heat radiation performance and, thus, PTV component performance and reliability. In one particularly innovative aspect of the present invention, the enclosure or cabinet includes panels that are formed from extruded material such as plastic. Moreover, an enclosure in accordance with the present invention preferably comprises hollow or partially hollow channels within the extruded panels.
In another particularly innovative aspect of the present invention, the enclosure or cabinet includes a ventilation duct having a first opening adjacent a lower compartment or the heat radiating components and a second opening adjacent the top of the enclosure or cabinet. Preferably, the first opening opens into the interior of the lower compartment of the enclosure, or simply adjacent the heat radiating components, and the second opening opens to the exterior of the enclosure at a location adjacent the top of the enclosure. Alternatively, the first opening of the ventilation duct opens to the interior of the enclosure adjacent the heat radiating components or lower compartment and the second opening also opens into the interior of the upper compartment adjacent the top of the enclosure.
In yet another innovative aspect of the present invention, the ventilation duct is formed from a hollow or partially hollow channel of an extruded enclosure panel.
Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings.